U.S. patent number 6,348,262 [Application Number 09/404,186] was granted by the patent office on 2002-02-19 for self adhesive tape and method of fabricating same.
This patent grant is currently assigned to Plastic Packaging Inc.. Invention is credited to Willard Huffman.
United States Patent |
6,348,262 |
Huffman |
February 19, 2002 |
Self adhesive tape and method of fabricating same
Abstract
A self adhesive tape which includes a substrate composed of a
clear plastic sheet, reverse printed indicia on one side of the
sheet, a flood coating of black or other colored ink overlying the
printed indicia, and an adhesive coating with a mesh fabric
reinforcement overlying the flood coating. The bottom surface of
the sheet is not treated or coated, which permits its original
gloss and sheen to be preserved, and so that the reverse printed
indicia is visible therethrough as a positive image.
Inventors: |
Huffman; Willard (Stoney Point,
NC) |
Assignee: |
Plastic Packaging Inc.
(Hickory, NC)
|
Family
ID: |
23598530 |
Appl.
No.: |
09/404,186 |
Filed: |
September 24, 1999 |
Current U.S.
Class: |
428/354;
427/208.4; 427/208.8; 428/343; 428/353; 428/906; 442/149;
442/151 |
Current CPC
Class: |
B44C
1/105 (20130101); C09J 7/0264 (20130101); C09J
2421/003 (20130101); C09J 2423/006 (20130101); Y10S
428/906 (20130101); Y10T 442/2754 (20150401); Y10T
442/2738 (20150401); Y10T 428/2843 (20150115); Y10T
428/2848 (20150115); Y10T 428/28 (20150115) |
Current International
Class: |
B44C
1/00 (20060101); B44C 1/10 (20060101); C09J
7/02 (20060101); C09J 007/02 () |
Field of
Search: |
;428/354,343,353,906
;442/149,151 ;427/208.4,208.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Zirker; Daniel
Attorney, Agent or Firm: Alston & Bird LLP
Claims
That which is claimed:
1. A self adhesive tape comprising
a substrate formed of a clear plastic sheet,
reverse printing applied to one side only of the sheet so that the
reverse printing is visible as a positive image when viewed through
the other side of the sheet,
a flood coating of ink applied to the one side of the sheet so as
to substantially cover the one side and the reverse printing,
and
a coating of an adhesive applied so as to substantially cover the
flood coating.
2. The self adhesive tape as defined in claim 1 wherein said one
side of said sheet is treated so as to enhance the adherence of the
reverse printing and the flood coating thereto.
3. The self adhesive tape as defined in claim 1 wherein the tape is
wound upon itself to form a roll, with the adhesive coating
directly contacting said other side of the sheet.
4. The self adhesive tape as defined in claim 3 wherein the roll is
wound so that the clear plastic sheet is on the outside of the
winds.
5. The self adhesive tape as defined in claim 4 wherein the
adhesive coating is formulated to provide a low-affinity for said
other side of the sheet, so as to permit the tape roll to be
readily unwound.
6. The self adhesive tape as defined in claim 4 wherein the
adhesive coating comprises an open mesh fabric reinforcement
embedded therein.
7. The self adhesive tape as defined in claim 1 wherein a primer is
interposed between the ink flood coating and the adhesive coating
to enhance the adherence of the adhesive coating to the ink flood
coating.
8. The self adhesive tape as defined in claim 1 wherein the clear
plastic sheet comprises polyethylene and has a thickness of about
2-3 mils.
9. A method of fabricating a self adhesive tape comprising the
steps of
providing a substrate of a clear plastic sheet,
treating one side of the sheet to provide an energized surface,
reverse printing upon the energized one side of the sheet so that
the reverse printing is visible as a positive image when viewed
through the other side of the sheet,
flood coating the one side of the sheet with ink so that the ink
substantially covers the one side and the reverse printing,
applying an adhesive coating to the one side of the sheet so that
the adhesive coating substantially covers the flood coating of ink,
and then
winding the sheet into a roll, with the adhesive coating adjacent
said other side of the sheet.
10. The method as defined in claim 9 wherein the adhesive coating
is formulated to provide a low-affinity for said other side of the
sheet, so as to permit the roll to be readily unwound.
11. The method as defined in claim 9 wherein the adhesive coating
comprises an open mesh fabric reinforcement embedded therein.
12. The method as defined in claim 11 comprising the further step
of applying a primer to the flood coating of ink which acts to
enhance the adherence of the later applied adhesive coating.
13. The method as defined in claim 12 wherein the primer comprises
a rubber based water emulsion.
14. The method as defined in claim 11 comprising, after the step of
applying an adhesive coating to the one side of the sheet, the
further step of passing the sheet through a pair of nip rolls to
force the adhesive through the open structure of the mesh fabric
reinforcement.
15. The method as defined in claim 9 wherein the winding step
includes having the adhesive coating directly contacting said other
side of the sheet.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a self adhesive tape of the type
commonly referred to as duct tape, and a method of fabricating
same.
Duct tape is conventionally fabricated by a process as illustrated
in FIG. 1, and wherein a sheet of black or otherwise colored
plastic film is printed on one side with product information, or
other indicia. In order to facilitate the adherence of the printing
to the surface of the sheet, the surface which receives the
printing may be initially corona or otherwise treated to provide a
roughened "high energy" surface. After printing, the opposite side
of the sheet is coated with an adhesive, which may include an
embedded mesh fabric reinforcement. Also, in some instances, the
back side of the sheet may also be "bump treated" as known in the
art to improve the adherence of the adhesive coating. Finally, the
sheet is slit and wound into rolls, with the print on the outside
of the winds and the adhesive on the inside of the winds.
While duct tape as constructed above is in widespread use,
difficulties have been encountered in permanently adhering the
adhesive coating to the back side of the sheet, and delamination
often occurs when the roll is unwound, particularly when the roll
has been subjected to relatively high heat. Also, with the adhesive
coating directly engaging the printing on the adjacent wind of the
role, the printing can be disfigured during the unwinding
operation.
It is an object of the present invention to provide an improved
self adhesive tape of the type described above, and which avoids or
at least significantly alleviates the above noted problems.
SUMMARY OF THE INVENTION
The above and other objects and advantages of the present invention
are achieved by the provision of a self adhesive tape which
comprises a substrate formed of a clear plastic sheet, and which
has reverse printing applied to one side only of the sheet so that
the reverse printing is visible as a positive image when viewed
through the other side of the sheet. A flood coating of ink is
applied to the printed side of the sheet so as to substantially
cover the reverse printing, and a coating of an adhesive is applied
so as to substantially cover the flood coating. The side of the
sheet which receives the printing may be initially treated so as to
roughen or "energize" its surface and thereby promote the adherence
of the printing and the flood coating thereto. As final steps, the
sheet may be slit to form a plurality of separate tapes, which are
each then wound upon itself to form a roll, with the adhesive
coating directly contacting the untreated back side of the sheet.
Also, the rolls are preferably wound so that the clear sheet is on
the outside of the winds, with the printing and adhesive on the
inside of the winds.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention will become
apparent as the description proceeds, when considered in
conjunction with the accompanying schematic drawings, in which
FIG. 1 is a flow diagram illustrating a prior art method of
fabricating duct tape, and
FIG. 2 is a flow diagram illustrating the product and method of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As illustrated in FIG. 2, the method of fabricating the tape of the
present invention starts with a backing sheet of clear plastic
film, such as polyethylene sheeting having a thickness of about 2-3
mils, and which forms the substrate for the resulting tape. The
backing sheet is treated on one side (the upper side as
illustrated) by a conventional chemical or corona treatment process
which serves to roughen or scratch the surface, and the treated
side is then printed by a reverse printing operation, so that the
reverse printing is visible as a positive image when viewed through
the other (i.e., bottom) surface of the sheet. As is conventionally
recognized, the scratched or roughened surface, commonly referred
to as an "energized" surface in the art, provides more surface area
for an improved adherence of the printing ink and later applied
other components.
The side of the sheet which has been reverse printed is then flood
coated with a colored ink, so as to form a contrasting background
when the printing is viewed through the other side of the clear
sheet. When the flood coating has dried, a primer may be applied to
the flood coating to enhance the adherence of the later applied
adhesive. The primer may comprise a rubber based water emulsion,
such as Hercules Res A-2603 or BASF Butofan.RTM. NS 166.
An adhesive and mesh (scrim) backing is applied over the flood
coating. The adhesive coating is formulated to provide a low
affinity for the untreated bottom side of the sheet when wound into
a roll, as further explained below. Also, after the application of
the adhesive and the mesh backing, the sheet may be run through a
pair of nip rolls, which forces the adhesive through the open
structure of the mesh backing. As a specific example, the adhesive
may comprise the following formulation:
natural or synthetic rubber 33% hydrocarbon resin 33% calcium 31%
naphtha oils 3%
The mesh reinforcement may comprise a conventional open mesh woven
fabric or scrim.
Finally, the sheet is slit and wound into rolls, with the adhesive
coating directly engaging the untreated bottom surface of the
sheet, and with the clear plastic sheet on the outside of the
winds.
The above process and formulation of the adhesive and primer
permits the adhesive to bond strongly to the flood coating of ink
and thus the top surface of the sheet, and bond less strongly to
the untreated bottom surface of the sheet when the tape is wound
into a roll. Thus the roll can be unwound with the adhesive coating
readily separating from the bottom surface and with little or no
delamination of the adhesive coating from the top surface.
All of the described operations can be performed by passing the
backing sheet through conventional automatic treating, printing,
coating, slitting, and winding equipment, so that the tape can be
readily fabricated in either a continuous or a discontinuous
process.
Since the above process eliminates the need to chemically or corona
treat, or coat, the bottom surface of the tape, the bottom surface
is able to retain its original gloss and sheen, which improves the
appearance of the product. Also, since the printed indicia and ink
flood coating are effectively encapsulated between the clear
backing sheet and the adhesive coating, they are not subject to
deterioration from abrasion against other surfaces.
Many modifications and other embodiments of the invention will come
to mind to one skilled in the art to which this invention pertains
having the benefit of the teachings presented in the foregoing
descriptions and the associated drawings. Therefore, it is to be
understood that the invention is not to be limited to the specific
embodiments disclosed and that modifications and other embodiments
are intended to be included within the scope of the appended
claims. Although specific terms are employed herein, they are used
in a generic and descriptive sense only and not for purposes of
limitation.
* * * * *